Photoelectric conversion panel and assembly thereof

ABSTRACT

In a photoelectric conversion panel which has a laminate member for photoelectric conversion use which includes a PIN type non-single-crystal laminate member formed on a substrate, the substrate is formed by a thin, flexible, chemically reinforced glass sheet. 
     A plurality of such photoelectric conversion panels are arranged side by side through using a flexible plastic frame reinforced with carbon fibers.

This is a divisional application of Ser. No. 614,211, filed May 25,1984, now U.S. Pat. No. 4,571,446.

BACKGROUND OF THE INVENTION

1. Field of the Invention

The present invention relates to a photoelectric conversion panel and anassembly comprised of a plurality of such panels.

2. Description of the Prior Art

A photoelectric conversion panel now widely employed is provided with alight-transparent substrate and a photoelectric conversion laminatemember formed thereon. The photoelectric conversion laminate member iscomprised of a light-transparent first conductive layer, a PIN typenon-single-crystal semiconductor laminate member, and a secondconductive layer laminated in this sequential order. The PIN typenon-single-crystal semiconductor layer includes at least a P- or N-typefirst non-single-crystal semiconductor layer, an I-type secondnon-single-crystal semiconductor layer formed on the firstnon-single-crystal semiconductor layer, and a third non-single-crystalsemiconductor layer formed on the second non-single-crystalsemiconductor layer and opposite in conductivity type from the firstnon-single-crystal semiconductor layer. Accordingly, the PIN typenon-single-crystal semiconductor layer has formed therein at least onePIN junction.

With such a photoelectric conversion panel, photovoltage is generatedacross the first and second conductive layers upon irradiation of thePIN type non-single-crystal semiconductor layer by light through thesubstrate and the first conductive layer. The photovoltage is providedto the outside via leads connected to the first and second conductivelayers.

Such a photoelectric conversion panel is usually installed outdoors, andhence is exposed to the weather. Accordingly, the substrate is subjectedto bending stresses by wind pressure.

Conventional photoelectric conversion panels usually have theirsubstrates formed by relatively thick and almost inflexible sheet glass.

The substrate of such sheet glass is broken when subjected to a bendingforce exceeding a certain value, resulting in the photoelectric panelgenerating no more photovoltage.

Further, the sheet glass forming the substrate is so brittle that itreadily cracks under stress or even when hit by a pebble.

The conventional photoelectric conversion panel is defective in thatsince the substrate is formed by relatively thick sheet glass, it isheavy and difficult to handle, coupled with the inflexibility andfragility of the substrate.

Conventionally there has also be employed a photoelectric conversionpanel assembly of the type wherein a plurality of such photoelectricconversion panels as mentioned above are mounted in a frame so that theyare arranged in substantially the same plane.

With such a photoelectric conversion panel assembly, it is possible togenerate high photovoltage by electrically connecting the photoelectricconversion panels in series and photovoltage of high current byelectrically connecting the panels in parallel.

In this case, however, since the photoelectric conversion panel assemblyis exposed to the weather, the frame of the panel assembly as well asthe substrate of each panel are subjected to bending stresses by windpressure.

The frame of such a conventional panel assembly usually has an aluminumframe which is almost inflexible.

As is the case with the abovesaid glass substrate, the aluminum frame,when subjected to a bending force exceeding a certain value, is broken,resulting in the panel assembly being broken up.

Besides, the conventional photoelectric conversion panel assembly isdifficult to handle, since its frame and panels are practicallyinflexible.

SUMMARY OF THE INVENTION

It is therefore an object of the present invention to provide a novelphotoelectric conversion panel free from the abovesaid defects and aphotoelectric conversion panel assembly which employs such photoelectricconversion panels and is also free form the abovementioned drawbacks ofthe prior art.

In accordance with an aspect of the present invention, thelight-transparent substrate of the photoelectric conversion panel isformed by a known thin, flexible, chemically reinforced glass sheetwhich has potassium glass layers formed in the sides of the oppositemain surfaces of an alkali free of alkali containing glass sheet.

With the photoelectric conversion panel of the present invention, sincethe substrate is formed by the abovesaid thin, flexible chemicalreinforced glass sheet, there is substantially no possiblity of thesubstrate being broken even if exposed to a high wind pressure. Further,the substrate does not crack when hit by a small object such as apebble. In addition, the substrate is lightweight. Accordingly, thesubstrate is suitable for use in photoelectric conversion panels whichare used under severe outdoor conditions.

In accordance with another aspect of the present invention, theabovesaid thin, flexible, chemically reinforced glass sheet serving asthe substrate is reinforced by carbon fibers or carbon cloths disposedin or on at least one main surface of the glass sheet. Accordingly, thesubstrate is mechanically strong as compared with the abovesaidsubstrate.

The photoelectric conversion panel with such a substrate also possessesthe same excellent features as those obtainable with the abovesaidphotoelectric conversion panel.

In accordance with another aspect of the present invention, thephotoelectric conversion panel has, between the thin, flexible,chemically reinforced glass sheet and the laminate member forphotoelectric conversion, an impurity blocking layer for preventingpotassium and impurities from entering into the latter from the former.The photoelectric conversion panel using such an impurity blocking layerpossesses the advantage that the characteristic of the laminate memberis not deteriorated by long-term use of the panel.

In accordance with another aspect of the present invention, thephotoelectric conversion panel assembly has such a construction that aplurality of such photoelectric conversion panels as mentioned above aremounted in a frame so that they are arranged in substantially the sameplane. In this case, the frame is formed by a flexible plasticreinforced by carbon fiber. With such a photoelectric conbversion panelassembly of the present invention, even if it is exposed to a strongwind, the frame bends, together with the photoelectric conversionpanels, so that the panel assembly is not damaged. Accordingly, thephotoelectric conversion panel assembly of the present invention is ofgreat utility in practical use.

Other objects, features and advantages of the present invention willbecome more fully apparent from the following description taken inconjunction with the accompanying drawings.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a schematic perspective view illustrating an example of thephotoelectric conversion panel assembly of the present invention whichemploys a pluralilty of photoelectric conversion panels of the presentinvention; and

FIG. 2 is a partly enlarged sectional view schematically showing anexample of the photoelectric conversion panel of the present invention.

DESCRIPTION OF THE PREFERRED EMBODIMENTS

FIG. 1 illustrates the photoelectric conversion panel assembly of thepresent invention, in which a plurality of photoelectric conversionpanels 1 of the present invention are disposed in the same plane. InFIG. 1, the panel assembly is shown to be comprised of four panels 1which are disposed in a matrix form.

As shown in FIG. 2, the photoelectric conversion panels 1 each measure,for example, 60×20 cm and comprise a light-transparent substrate 3 and alaminate member 4 formed thereon for photoelectric conversion use.

The substrate 3 is a known thin, flexible, chemically reinforced glasssheet 8 which has thin potassium glass layers 6 and 7 formed 40 to 50μthick in opposite main surfaces of a thin alkali free or alkalicontaining glass sheet 5 having a thickness of 0.2 to 1.2 mm. In thecase where the glass sheet 5 is a sodium glass sheet, potassium glasslayers 6 and 7 each have a structure wherein sodium present in the sidesof the main surfaces of the sodium glass sheet have been replaced withpotassium having a larger atomic radius than the sodium. When the glasssheet 5 is the alkali free glass sheet, the potassium glass layers 6 and7 each have a structure wherein the sides of the main surfaces of thealkali free glass sheet each have introduced therein potassium.

By virtue of the inclusion of the potassium glass layers 6 and 7, thethin, flexible, chemically reinforced glass sheet 8 has such greatflexibility that it can be bent with a bend radius of 1 to 2 m, i.e.,less than 3 m.

Such a glass sheet 8 may be provided therein or on at least one mainsurface thereof with carbon fibers disposed in a mesh- or grid-like formor at random, or carbon fiber cloths. The glass sheet 8 with such carbonfibers or carbon fiber cloths has greater flexibility than in the casewhen such carbon fibers or carbon fiber cloths are not used.

The laminate member 4, formed on the thin, flexible, chemicallyreinforced glass sheet 8 serving as the light-transparent substrate 3,has a known structure comprising a light-transparent conductive layer10, a PIN junction type non-single-crystal semiconductor laminate member11, and a conductive layer 17 laminated in this sequential order. Thelaminate member 11 is, for example, 0.3 to 1μ thick. The conductivelayers each are for example, 0.05 to 0.3 μm thick.

The PIN type non-single-crystal semiconductor layer 11 is composed of aP- or N-type non-single-crystal semiconductor layer 12, an I-typenon-single-crystal semiconductor layer 13 formed on the layer 12, and anon-single-crystal semiconductor layer 14 formed on the layer 13 andopposite in conductivity type from the layer 12. Accordingly, the PINtype non-single-crystal semiconductor layer 11 has formed therein onePIN junction.

It is preferable that between the light-transparent substrate 3 formedby the thin, flexible, chemically reinforced glass sheet 8 and thelaminate member 4 for photoelectric conversion use there be provided animpurity blocking layer 18 for preventing the introduction of potassiumand other impurities from the glass sheet 8 into the laminate member 4.The impurity blocking layer 18 may be formed of a silicon nitride (Si₃N₄), for instance.

The laminate member 4 for photoelectric conversion is covered with aprotective layer 19 of a resinous material. An impurity blocking layer15 similar to the abovesaid layer 18 may preferably be formed betweenthe laminate member 4 and the protective layer 19. The impurity blockinglayer 15 is intended to prevent raindrops and impurities containedtherein from entering into the laminate member 4 through the protectivelayer 19.

A frame 2 supporting such photoelectric conversion panels 1 inside-by-side relation is formed by a known flexible plastic frame 16reinforced with carbon fibers. The flexible plastic frame 16 is flexibleto substantially the same extent as the photoelectric conversion panel1.

Accordingly, even if the photoelectric conversion panel assembly of thepresent invention is subjected to bending stresses as by wind pressure,the frame 1 ensures absorption of the bending stresses.

The photoelectric conversion panel assembly of the present inventionshown in FIG. 1 is used with the panels electrically connected in seriesor in parallel and with the light-transparent substrates 3 of the panelsfacing a light source.

When the photoelectric conversion panel assembly shown in FIG. 1 issubjected to large bending stresses, the photoelectric conversion panels1 and the frame 2 are bent, so that the panel assembly is also bentcorrespondingly. In this case, the laminate member 4 for photoelectricconversion use formed on the substrate 3 of each photoelectricconversiodn panel 1 is also bent, but this poses substantially noproblems partly because the laminate member 4 is thin and partly becausethe PIN type non-single-crystal semiconductor laminate member 11 isformed of a non-single-crystal semiconductor. Accordingly, even ifexposed to large bending stresses, the panel assembly would not bebroken even if hit by an object such as a pebble. Besides, the panelassembly of the present invention is lightweight, and hence is easy tohandle. In addition, the impurity blocking layers 13 and 15 of eachphotoelectirc conversion panel 1 prevent the photoelectric conversionefficiency from being lowered by long-time use.

While in the foregoing the photoelectric conversion panel of the presentinvention has been described, along with the panel assembly, it will beapparent that many modifications and variations may be effected withoutdeparting from the scope of the novel concepts of the present invention.

What is claimed is:
 1. A photoelectric conversion panel comprising:a light-transparent substrate having a potassium containing surface layer; a laminated member formed on the light-transparent substrate and comprising, in sequence, a light-transparent first conductive layer, at least one PIN type non-single-crystal semiconductor laminate photoelectric conversion member, and a second conductive layer; a first impurity blocking layer formed of silicon nitride and provided between the light-transparent substrate and the laminate member for preventing entrance of unnecessary impurities into the laminate member from the light-transparent substrate; and a second impurity blocking layer formed on the laminate member for preventing entrance of unnecessary impurities into the laminate member from the outside.
 2. A photoelectric conversion panel according to claim 1, which further comprises a protective layer formed on the second impurity blocking layer.
 3. A photoelectric conversion panel assembly comprising:a plurality of photoelectric conversion panels disposed side by side in a frame; wherein each photoelectric conversion panel comprises a light-transparent substrate having a potassium containing surface layer, a laminated member formed on the light-transparent substrate and comprising, in sequence, a light-transparent first conductive layer, at least one PIN type non-single-crystal semiconductor laminate photoelectric conversion member, and a second conductive layer, a first impurity blocking layer formed of silicon nitride and provided between the light-transparent substrate and the laminate member for preventing entrance of unnecessary impurities into the laminate member from the light-transparent substrate, and a second impurity blocking layer formed on the laminate member for preventing entrance of unnecessary impurities into the laminate member from the outside.
 4. A photoelectric conversion panel assembly according to claim 3, wherein each photoelectric conversion panel further comprises a protective layer formed on the second impurity blocking layer. 